checking, if a file exists
- To: mathgroup at smc.vnet.net
- Subject: [mg84383] checking, if a file exists
- From: vejrazka at icpf.cas.cz
- Date: Thu, 20 Dec 2007 16:50:02 -0500 (EST)
Hello,
I am new to Mathematica & I have the following problem: I need to
1. check, if a file ("data.dat") with some computationally intensive
results exists
2. if yes, read the file
3. if no, do the calculation
I have written (in Mathematica 6) the following:
fileName = "...some path ... \\data.dat";
data = If[FileType[fileName] == File, Import[fileName],
calculate[0]]
It reads correctly the data if the file exists. But if the file does
not exists, it returns
If[None == File, Import[fileName], calculate[0]]
Evidently, the problem is, that
FileType[fileName] == File
returns correctly True if the file exists, but it does not return
False when the file is missing -- it returns only None == File.
How to do that?
Thank you.
Jiri